High-fidelity texture display via programmable friction

We present two surface haptic displays capable of rendering high-frequency textural content directly to the fingertip exploring the device. The friction of the fingertip with the glass plate is modulated either by electrostatic attraction or ultrasonic out-of-plane vibration. The unique rendering capabilities of these devices is possible to a high-speed non-contact position sensing and haptic rendering computed on a real-time embedded controller with a 5000 Hz update rate. As the finger explores the virtual surface the friction reduction signal, a sine wave at ultrasonic frequency, is modulated with the friction force profile of the texture, encoded in space. The combination of high-speed position sensing and low latency haptic rendering results in a vivid sense of spatial tactile feature, unlike anything perceived on devices that exhibit longer finger position delays.